1. Field of the Invention
The present invention relates to a water well device.
2. Description of the Prior Art
A water well is basically constructed such that a space is formed in a water stratum, and groundwater is collected into the space and pumped up.
Hydrographically, the ideal form is the `dig and leave` construction. That is, well walls are left to be a natural water layer, and no barrier is provided so that groundwater freely flows into the well in a natural state.
However, in the `dig and leave` condition, the well walls are soon broken down, and therefore, stones are compelled to be stacked. Or, pipes A such as concrete pipes, iron pipes, plastic pipes or the like are incorporated to form protective walls as shown in FIG. 1 so that groundwater may flow into the well through the protective walls. Therefore, open portions B, B . . . obtained by the provision of holes, slits and screen need be provided. However, the percentage of open area of these open portions B, B . . . to well wall surfaces, that is, the open percentage is less than 35% at the most.
Accordingly, in conventional water wells, particularly, pipe wells, it is designed so that the open portions B, B . . . are provided only in the peripheral surfaces of the protective walls. For this reason, a water collecting area required for flow-in of groundwater is excessively small. This brings forth (1) increase in well loss, (2) densification of the water layer about the well, (3) occurrence of jamming of the open portions, and (4) flow-in of earth and sand, etc.
Due to the aforesaid (1) increase in well loss, power consumption for drawing water increases; due to the aforesaid (2) and (3) densification in water layer and jamming, durable years of a well are shortened; and due to the aforesaid (4) flow-in of earth and sand, pumping-up equipment such as pumping-up pumps, screens and the like are worn and damaged.
There poses problems in maintenance induced from the aforementioned factors, in that installation of a device for settling and filtering earth and sand and management cost are necessary, a periodical cost of cleaning the interior of a well is required, and a great loss is brought forth in that with a loss due to the stoppage of pumping-up operation, the synthetic service life of the well is further shortened.
Various defects of the above-described well device will be discussed. First, a water collecting area is absolutely short. Secondly, water collection is achieved by the flowing-in only in a horizontal direction refracted by 90.degree. despite the fact that a descent of groundwater at the time of pumping-up acts in a direction of gravity, and therefore, the resistance increases. Thirdly, since the water collecting area is small, inlet velocity of groundwater extremely increases, as a consequence of which a discontinuity (loss of well) occurs between groundwater and a leaching surface, inviting entry of earth and sand. In addition, in the conventional well, a part of open portions of the well walls is exposed to an upper surface of a water level, and therefore, jamming is accelerated by break down of the stratum due to drying resulting from contact of said part with air, corrosion due to oxidizing action, generation of scale and the like, thus shortening durable years. Pumping power cost is wastefully consumed due to the lowering of water level by a loss portion of well.